STRUCT SSI_PROTOCOL(9)

✨ struct ssi_protocol(9) ✨

okay bestie, welcome to the struct ssi_protocol glow-up 💅 this is a page from the Kernel API Manual, and we're about to go through the SSI protocol (McSAAB) data struct together like it's a group project we're actually going to slay 🫶

🌸 NAME 🌸

struct ssi_protocol — the SSI protocol (McSAAB) data. that's it, that's the vibe ✨

🎀 SYNOPSIS 🎀

struct ssi_protocol {
    unsigned int            main_state;
    unsigned int            send_state;
    unsigned int            recv_state;
    unsigned long           flags;
    u8 rxid;
    u8 txid;
    unsigned int            txqueue_len;
    struct timer_list       tx_wd;
    struct timer_list       rx_wd;
    struct timer_list       keep_alive;
    spinlock_t lock;
    struct net_device       *netdev;
    struct list_head        txqueue;
    struct list_head        cmdqueue;
    struct work_struct      work;
    struct hsi_client       *cl;
    struct list_head        link;
    atomic_t tx_usecnt;
    int channel_id_cmd;
    int channel_id_data;
 };

like yes, she's got range 💖 twenty members and not one of them is filler.

👑 MEMBERS 👑

every single one of these is a main character, so let's give them their moment 🌟

• main_state — the main state machine. she runs the whole show, no cap.
• send_state — the TX state machine. the sending side of things 📤
• recv_state — the RX state machine. the receiving side 🛬
• flags — flags! rn they're only used to follow the wake line test, that's her whole job rn and she's doing it.
• rxid — the RX data id.
• txid — the TX data id.
• txqueue_len — how long the TX queue is. literally the TX queue length 📏
• tx_wd — the TX watchdog. she's watching 👀
• rx_wd — the RX watchdog. also watching 🐕
• keep_alive — a workaround for an SSI HW bug. iconic of her to say it like that, honestly.
• lock — exists to serialize access to this struct 🔒 so everybody takes turns, periodt.
• netdev — the Phonet network device.
• txqueue — the TX data queue.
• cmdqueue — the queue of free commands.
• work — a struct work_struct for scheduled work 🛠️
• cl — the HSI client own reference.
• link — the link for ssip_list.
• tx_usecnt — a refcount to keep track of the slaves that use the wake line. she's counting, bestie 🧮
• channel_id_cmd — the HSI channel id for the command stream.
• channel_id_data — the HSI channel id for the data stream.

🦋 SEE ALSO 🦋

the kernel file ./drivers/hsi/clients/ssi_protocol.c — go read the source, iykyk 💜

and that's the whole page, bestie 🌈 this cutie lives in ./drivers/hsi/clients, dated October 2026, and she answers to struct ssi_protocol(9) whenever you call her name 💖✨🎀